1// SPDX-License-Identifier: (GPL-2.0+ OR BSD-3-Clause)
2/*
3 * Driver for the onsemi 10BASE-T1S NCN26000 PHYs family.
4 *
5 * Copyright 2022 onsemi
6 */
7#include <linux/kernel.h>
8#include <linux/bitfield.h>
9#include <linux/errno.h>
10#include <linux/init.h>
11#include <linux/module.h>
12#include <linux/mii.h>
13#include <linux/phy.h>
14
15#include "mdio-open-alliance.h"
16
17#define PHY_ID_NCN26000 0x180FF5A1
18
19#define NCN26000_REG_IRQ_CTL 16
20#define NCN26000_REG_IRQ_STATUS 17
21
22// the NCN26000 maps link_ctrl to BMCR_ANENABLE
23#define NCN26000_BCMR_LINK_CTRL_BIT BMCR_ANENABLE
24
25// the NCN26000 maps link_status to BMSR_ANEGCOMPLETE
26#define NCN26000_BMSR_LINK_STATUS_BIT BMSR_ANEGCOMPLETE
27
28#define NCN26000_IRQ_LINKST_BIT BIT(0)
29#define NCN26000_IRQ_PLCAST_BIT BIT(1)
30#define NCN26000_IRQ_LJABBER_BIT BIT(2)
31#define NCN26000_IRQ_RJABBER_BIT BIT(3)
32#define NCN26000_IRQ_PLCAREC_BIT BIT(4)
33#define NCN26000_IRQ_PHYSCOL_BIT BIT(5)
34#define NCN26000_IRQ_RESET_BIT BIT(15)
35
36#define TO_TMR_DEFAULT 32
37
38static int ncn26000_config_init(struct phy_device *phydev)
39{
40 /* HW bug workaround: the default value of the PLCA TO_TIMER should be
41 * 32, where the current version of NCN26000 reports 24. This will be
42 * fixed in future PHY versions. For the time being, we force the
43 * correct default here.
44 */
45 return phy_write_mmd(phydev, MDIO_MMD_VEND2, MDIO_OATC14_PLCA_TOTMR,
46 TO_TMR_DEFAULT);
47}
48
49static int ncn26000_config_aneg(struct phy_device *phydev)
50{
51 /* Note: the NCN26000 supports only P2MP link mode. Therefore, AN is not
52 * supported. However, this function is invoked by phylib to enable the
53 * PHY, regardless of the AN support.
54 */
55 phydev->mdix_ctrl = ETH_TP_MDI_AUTO;
56 phydev->mdix = ETH_TP_MDI;
57
58 // bring up the link
59 return phy_write(phydev, MII_BMCR, NCN26000_BCMR_LINK_CTRL_BIT);
60}
61
62static int ncn26000_read_status(struct phy_device *phydev)
63{
64 /* The NCN26000 reports NCN26000_LINK_STATUS_BIT if the link status of
65 * the PHY is up. It further reports the logical AND of the link status
66 * and the PLCA status in the BMSR_LSTATUS bit.
67 */
68 int ret;
69
70 /* The link state is latched low so that momentary link
71 * drops can be detected. Do not double-read the status
72 * in polling mode to detect such short link drops except
73 * the link was already down.
74 */
75 if (!phy_polling_mode(phydev) || !phydev->link) {
76 ret = phy_read(phydev, MII_BMSR);
77 if (ret < 0)
78 return ret;
79 else if (ret & NCN26000_BMSR_LINK_STATUS_BIT)
80 goto upd_link;
81 }
82
83 ret = phy_read(phydev, MII_BMSR);
84 if (ret < 0)
85 return ret;
86
87upd_link:
88 // update link status
89 if (ret & NCN26000_BMSR_LINK_STATUS_BIT) {
90 phydev->link = 1;
91 phydev->pause = 0;
92 phydev->duplex = DUPLEX_HALF;
93 phydev->speed = SPEED_10;
94 } else {
95 phydev->link = 0;
96 phydev->duplex = DUPLEX_UNKNOWN;
97 phydev->speed = SPEED_UNKNOWN;
98 }
99
100 return 0;
101}
102
103static irqreturn_t ncn26000_handle_interrupt(struct phy_device *phydev)
104{
105 int ret;
106
107 // read and aknowledge the IRQ status register
108 ret = phy_read(phydev, NCN26000_REG_IRQ_STATUS);
109
110 // check only link status changes
111 if (ret < 0 || (ret & NCN26000_REG_IRQ_STATUS) == 0)
112 return IRQ_NONE;
113
114 phy_trigger_machine(phydev);
115 return IRQ_HANDLED;
116}
117
118static int ncn26000_config_intr(struct phy_device *phydev)
119{
120 int ret;
121 u16 irqe;
122
123 if (phydev->interrupts == PHY_INTERRUPT_ENABLED) {
124 // acknowledge IRQs
125 ret = phy_read(phydev, NCN26000_REG_IRQ_STATUS);
126 if (ret < 0)
127 return ret;
128
129 // get link status notifications
130 irqe = NCN26000_IRQ_LINKST_BIT;
131 } else {
132 // disable all IRQs
133 irqe = 0;
134 }
135
136 ret = phy_write(phydev, NCN26000_REG_IRQ_CTL, val: irqe);
137 if (ret != 0)
138 return ret;
139
140 return 0;
141}
142
143static struct phy_driver ncn26000_driver[] = {
144 {
145 PHY_ID_MATCH_MODEL(PHY_ID_NCN26000),
146 .name = "NCN26000",
147 .features = PHY_BASIC_T1S_P2MP_FEATURES,
148 .config_init = ncn26000_config_init,
149 .config_intr = ncn26000_config_intr,
150 .config_aneg = ncn26000_config_aneg,
151 .read_status = ncn26000_read_status,
152 .handle_interrupt = ncn26000_handle_interrupt,
153 .get_plca_cfg = genphy_c45_plca_get_cfg,
154 .set_plca_cfg = genphy_c45_plca_set_cfg,
155 .get_plca_status = genphy_c45_plca_get_status,
156 .soft_reset = genphy_soft_reset,
157 },
158};
159
160module_phy_driver(ncn26000_driver);
161
162static struct mdio_device_id __maybe_unused ncn26000_tbl[] = {
163 { PHY_ID_MATCH_MODEL(PHY_ID_NCN26000) },
164 { }
165};
166
167MODULE_DEVICE_TABLE(mdio, ncn26000_tbl);
168
169MODULE_AUTHOR("Piergiorgio Beruto");
170MODULE_DESCRIPTION("onsemi 10BASE-T1S PHY driver");
171MODULE_LICENSE("Dual BSD/GPL");
172

source code of linux/drivers/net/phy/ncn26000.c